The problem of filtering a liquid containing contaminant particles in industrial applications without excessive manual operations or overly complex mechanical structure has long persisted. For example, the water used in washer sections of air handling systems of textile and paper mills contains contaminants in large volume necessitating frequent cleaning of the entire system.
It is an important object of this invention to provide a practical apparatus and method for filtering the water used in a washer section of an air handling system, and the like.
In industrial filtering applications efforts have been made to provide liquid filtering apparatus having submerged filter media that can be replaced without interruption of the filtering operation. For example, apparatus for so replacing the filter media is illustrated in U.S. Pat. Nos. 3,083,831; 3,087,620; 3,333,693 and 3,333,705. These filters use a dual chamber system wherein one chamber is superposed upon another. Such patents exhibit relatively complicated devices, affording limited filter area requiring frequent changes of filter medium, with elaborate mechanism to avoid leakage of contaminated liquid around the edges of the filter medium.
Drum filters of the vacuum type employing permanent filter medium, such as shown in U.S. Pat. Nos. 2,812,064 and 2,812,065 are sealed from the atmosphere with peripheral pockets connected with a central sleeve by spaced suction pipes. U.S. Pat. No. 1,816,132 discloses a compartmentalized drum filter wherein the level of the outflowing water inside a sieve is lower than the level of the contaminated liquid outside it. The drum filter of U.S. Pat. No. 3,651,946 employs suction through a central shaft to remove filtered liquid from the drum and to produce the filtering action.
Accordingly, an important object of this invention is to provide a simplified apparatus and method operable with a minimum of moving operations to afford a continuous liquid filtering system.
Another object of this invention is to provide a liquid filter affording a maximum of filter area affording increased flow with less changes of filter medium.
Still another important object of this invention is to provide simplified means to avoid leakage of contaminated liquid around the edges of the filter medium.